Power semiconductor device such as power MOSFETs (Metal Oxide Field-Effect Transistors), power IGBTs (Insulated Gate Bipolar Transistors), power diodes or power thyristors are widely used in industrial, automotive, household, or consumer electronic applications. A power semiconductor device includes a drift region (which may also be referred to as base region) that mainly defines a voltage blocking capability of the semiconductor device. A power semiconductor device may be operated in a bipolar conduction mode in which there is a charge carrier plasma with charge carriers of one type (electrons or holes) and charge carriers of a complementary type in the drift region. A MOSFET, for example, is in the bipolar conduction state when an internal body diode formed by the drift region and an adjoining body region is forward biased and conducting. The charge carrier plasma is removed when the device changes from the bipolar conducting state to the blocking state. A time duration it takes for this charge carrier plasma to be removed, that is, a time duration it takes for the device to change from the bipolar conducting state to a blocking state is dependent on a concentration of charge carriers that form the plasma.
The charge carrier concentration and, therefore, the characteristic of the semiconductor device when changing from the bipolar conducting state to the blocking state can be adjusted by forming recombination centers in the drift region. These recombination centers promote a recombination of electrons and holes in the drift and, therefore, help to adjust the plasma concentration. Forming recombination centers may include introducing recombination center atoms, such as platinum atoms, into the drift region during a manufacturing process of the semiconductor device. Some of these recombination center atoms, however, may diffuse out of the semiconductor body during a subsequent processing and may contaminate processing equipment.
There is therefore a need for producing recombination centers in a semiconductor device while reducing a risk of contamination of processing equipment.